Quote:
 Greetings:
Love those Runners!
My tallest Runners are about 24 inches tall.  So it might be a bit low for them.  Others use fairly short shelters, though, only for nighttime.  Any way to raise the roof?  Another way of looking at it is that for most of their ducklinghood, it might be just the right size, and only too short once they reach full height, at about ten weeks of age.  Hmmmm.  
Square footage wise, it's a bit tiny for anything more than overnight, and if we (I'm across the Sound from you) get a serious Nor'easter, it might be way too cramped for a day or four at a time.  You  may need a Plan B for extended weather events, like letting them move into the house with you . . . . 
Pros of sharing run with chickens - might be less management effort on your part to have one run.  Cons?  Drakes mating with chicken hens - very bad for the hens.  Chickens fail to appreciate ducks' approach to the enjoyment of water.  The former get disgusted with the latter's habit of making a muddy murky mess of water.  And, again, many people keep their chickens and ducks together much if not all the time.  It really depends on the flock dynamics and individual personalities of ducks and people.  You might try it, again with a Plan B in mind.
Okay in winter?  In my experience, the Runners did not thrive in temperatures below 30F.  And . . . (you see this coming, yes?) many on the BYC Duck Forum declare that Runners have no problems out in the cold.  A number of them, though, when I asked, indicated that the shelters they use stay around 40F minimum.  I decided not to try to prove anything, and in the cold weather the ducks sleep in a pen in the walkout unfinished basement.  Easier on me, too, remember last year's snow?  Over here we had three feet of snow for weeks.  
There are people on the forum who supplement with black oil sunflower seeds.  See if a search of the forum turns up the details.  I add wheat berries and rolled oats and millet as extras sometimes, and that seems to be no trouble.  There are seeds with little hairs on them.  Awns, I think they're called by botanists.  Those can definitely give you trouble.  Nettie's Runner had an awful time with them once.
For swim pans, I use concrete mixing pans (black tubs) and a puppy pool someone gave me.  They work fine, and it does seem to me that in a sunny place, the black pans do stay a little warmer, and ice up a little less.  I change drinking water two or three times per 24 hours (it's a nice deep, flat bottomed soup pot), and swim pans every other day unless it's well below freezing at night, in which case I dump the water in the evening after the ducks are in to prevent dealing with a solid mass of ice in the morning.  I drain the hoses, too, so I can use them in the a.m.
In the summer I change the water daily most days.  When it's in the mid 90s and above, I refresh swim water around 1 or 2 p.m. just to give them a break from the heat.
Hope this helps!
I'd like to use the house just for the night.  Yes, I could raise the roof, but would rather not have to.  I suppose I could wait till they are big enough when it'll will most likely nag at me to raise it.d
I have a shed right next to the chickens that I can use in case of an emergency like bad weather and I have a big dog crate.
I'm put off a bit on how often I'd need to change the water.  Once  a day or every other is what I do for the chicken's drinking water.  Maybe I need to set up a draining system and a hose right next to the pond.  What if I'm gone for an entire day and can't clean the swimming water?
Thanks for all your help!